Contaminant salts as enhancers of sonocatalytic degradation of organic water pollutants: Effect of concentration, reaction time and adsorption on the efficiency of enhancement and the fate of concurrently formed H 2 O 2

Jyothi, K. P.; Yesodharan, Suguna; Yesodharan, E.P.

doi:10.1016/j.jece.2016.12.053

Cited by 27 publications

(9 citation statements)

References 87 publications

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“…This is probably because the anions scavenge the hydroxyl radicals, transforming them into the respective anionic radicals, which are less efficient (see Eqs. (3.3) – (3.5) ) [ 42 , 43 ].…”

Section: Resultsmentioning

confidence: 99%

Sonophotocatalytic degradation mechanisms of Rhodamine B dye via radicals generation by micro- and nano-particles of ZnO

Lops

Ancona

Cesare

et al. 2019

Applied Catalysis B: Environmental

412

148

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In this work, it is proposed an environmental friendly sonophotocatalytic approach to efficiently treat polluted waters from industrial dyes exploiting ZnO micro- and nano-materials. For the first time, we deeply investigated the generation of reactive oxygen species (ROS) under ultrasound stimulation of different ZnO structures by Electron Paramagnetic Resonance Spectroscopy (EPR). Indeed, five zinc oxide (ZnO) micro- and nano-structures, i.e. Desert Roses (DRs), Multipods (MPs), Microwires (MWs), Nanoparticles (NPs) and Nanowires (NWs), were studied for the Rhodamine B (RhB) sonodegradation under ultrasonic irradiation. The DRs microparticles demonstrated the best sonocatalytic performance (100% degradation of RhB in 180 min) and the highest OH· radicals generation under ultrasonic irradiation. Strikingly, the coupling of ultrasound and sun-light irradiation in a sonophotodegradation approach led to 100% degradation efficiency, i.e. color reduction, of RhB in just 10 min, revealing a great positive synergy between the photocatalytic and sonocatalytic mechanisms. The RhB sonophotocatalytic degradation was also evaluated at different initial dye concentrations and with the presence of anions in solution. It was demonstrated a good stability over repeated cycles of dye treatment, which probe the applicability of this technique with industrial effluents. In conclusion, sonophotocatalytic degradation synergizing sunlight and ultrasound in the presence of DRs microparticles shows a great potential and a starting point to investigate further the efficient treatment of organic dyes in wastewater.

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Section: Resultsmentioning

confidence: 99%

Sonophotocatalytic degradation mechanisms of Rhodamine B dye via radicals generation by micro- and nano-particles of ZnO

Lops

Ancona

Cesare

et al. 2019

Applied Catalysis B: Environmental

412

148

View full text Add to dashboard Cite

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“…Anions are often present in natural water systems and hence the study of the effect of anions on the sonocatalytic degradation of pollutants is important, especially in the context of commercial application of the process. Reports are available on the enhancing as well as inhibiting effect of anions on the sonocatalytic degradation of water pollutants [75] . In the present study the effect of PO 4 3− , HCO 3 − , CO 3 2− , NO 3 − , SO 4 2− , CH 3 COO − and Cl − on the degradation of IC is investigated under the optimized conditions of other parameters.…”

Section: Resultsmentioning

confidence: 99%

“…Since the concentration of the salt and the reaction time are known to influence the anion effect significantly [75] , detailed investigation on the effect of these two parameters is made and the results are summarized in Table 4 .…”

Section: Resultsmentioning

confidence: 99%

“…Thus photocatalysis and possibly mild sonophotocatalysis and consequent degradation of IC are also taking place in the sonocatalytic system. The net concentration of · OH radicals in the system at any point in time depends on the relative rates of their generation and decomposition [ 5 , 75 ]. The formation of · OH radicals under MnO 2 sonocatalysis is experimentally verified by the photoluminescence (PL) spectral studies (Section 2.3 ) as is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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MnO2 efficiently removes indigo carmine dyes from polluted water

Lekshmi

Yesodharan

2018

Heliyon

Self Cite

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MnO2 is identified as a highly efficient sonocatalyst and sonophotocatalyst for the complete removal of even very small concentration of Indigo carmine (IC) dye pollutant from water. The effect of various reaction parameters, viz. dosage of the catalyst, concentration of pollutant, volume of reaction system, pH, dissolved gases, presence of anions/salts and oxidants etc. on the rate of degradation is evaluated and optimum parameters are identified. The degradation follows variable kinetics depending on the concentration of the substrate. The rate of degradation is facilitated by acidic pH. Classic oxidants H2O2 and S2O82− behave differently, with the former inhibiting and the latter enhancing the degradation. The effect of anions/salts on the degradation is complex and ranges from ‘inhibition’ (PO43−, CO32−, HCO3−) and ‘no effect’ (SO42−, Cl−) to ‘enhancement’ (NO3−, CH3COO−). The high affinity of MnO2 for O2 and its extremely efficient adsorption of H2O2 and the substrate play key roles in the efficiency of the process. Participation of lattice oxygen from MnO2 in the reaction, whenever the dissolved or adsorbed oxygen is deficient, is an important highlight of the process. Major transient intermediates formed during the process are identified by LC–MS. Combination of sonocatalysis with UV photolysis (sonophotocatalysis) enhances the efficiency of degradation and mineralization of IC.

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“…In these processes, highly reactive oxidizing radicals (e.g., • OH) are produced that react with organic pollutants and convert them into harmless products [22] . Acoustic cavitation is classified as an AOP since it generates highly reactive oxidizing radicals within cavitation bubbles that have been used in environmental remediation for the degradation of pollutants in aqueous solutions [23] , [24] , [25] , [26] . Photocatalysis, Fenton process, ozonation, electro-chemical/catalytic techniques, etc, also generated highly reactive radicals that are used for the degradation of organic pollutants [27] , [28] , [29] , [30] , [31] , [32] , [33] .…”

Section: Introductionmentioning

confidence: 99%

Preparation of MgTi2O5 nanoparticles for sonophotocatalytic degradation of triphenylmethane dyes

Selvamani

Anandan

Asiri

et al. 2021

Ultrasonics Sonochemistry

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Contaminant salts as enhancers of sonocatalytic degradation of organic water pollutants: Effect of concentration, reaction time and adsorption on the efficiency of enhancement and the fate of concurrently formed H 2 O 2

Cited by 27 publications

References 87 publications

Sonophotocatalytic degradation mechanisms of Rhodamine B dye via radicals generation by micro- and nano-particles of ZnO

Sonophotocatalytic degradation mechanisms of Rhodamine B dye via radicals generation by micro- and nano-particles of ZnO

MnO2 efficiently removes indigo carmine dyes from polluted water

Preparation of MgTi2O5 nanoparticles for sonophotocatalytic degradation of triphenylmethane dyes

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